In the case of tire-related breakdowns, there is generally the problem that—as has hitherto been conventional for example in a passenger motor vehicle—a filled spare tire mounted on a wheel rim must be carried on board, which spare tire is then fitted in place of the wheel with the defective tire, following which the defective tire must be fastened in the stowage space provided in the vehicle for the spare tire and later taken for repair. For this purpose, it is not only often necessary to unload a laden vehicle in order to access the corresponding stowage space, but it is also necessary for the vehicle itself to be raised using vehicle jacks, and for cumbersome repair work to be performed.
To avoid these disadvantages, repair sets or breakdown kits are already known which include a compressor, a sealant which coagulates in the tire, normally a latex milk mixture, the corresponding connecting hoses and the required cable connections for the supply of energy, and also a switch, manometer and operating element, and which thus provide a permanently usable and complete repair set, with which it is possible to dispense with carrying on board a spare wheel fitted on a wheel rim, or with the constant inspection of other repair materials such as hoses, various tool wrenches, vehicle jacks, et cetera.
Accordingly, DE 29812740 U1 discloses a repair set with a portable container for accommodating on-board tools and working appliances for vehicles, in particular for accommodating a compressor, tools, working appliances and accessories for repairing tires, wherein the container is in the form of a luggage case and contains multiple compartments for the accessories and switching, control and display devices.
The operation of such repair sets is however not entirely simple, in particular if, depending on the operating state, it is firstly necessary for a sealant container and various hose connections to be attached or refitted. Specifically, most repair sets are also very highly suitable for being used, without a sealant insert, merely for inflating tires, inflatable boats, air mattresses et cetera. Owing to the fact that tire-related breakdowns nowadays occur only rarely, the repair sets are generally used more frequently for such leisure purposes than for emergencies. If this however does occur, the user is in an unfamiliar and unpractised situation.
To facilitate the handling of the appliances/repair sets in such different usage situations, solutions are already known in the prior art which substantially involve a simplified switchover from one to the other operation type. Solutions also exist which have plug-type connections between individual parts of the appliances/repair sets.
Aside from this actual object of sealing a damaged tire, the described air compressors are self-evidently frequently also used for inspecting and possibly adapting the tire pressure in a non-damaged tire. In this operating state, it is normally the case that no sealant bottle is connected to the connection piece of the air compressor, and the connector provided for this purpose is closed off in air-tight fashion, often via a cap. Accordingly, by connecting the air compressor to the vehicle tire, the end user can read off the air pressure thereof on a manometer that is normally integrated into the air compressor, and can if necessary increase the air pressure in the tire by activating the air compressor.
This all has the effect that, not only in the event of tire repairs but also in the other applications mentioned, in practical use, a function of lowering the tire pressure is self-evidently also necessary in addition to the increasing of the pressure/tire pressure. Normally, for this purpose, a discharge valve that can be actuated by the user is integrated into the air compressor or into the feed line to the tire.
Here, in the prior art, it is customary for a discharge valve to be permanently installed into the line system, such that the discharge valve can be manually operated by the user in all operating states of the air compressor. Since sealant is however also delivered through the line system when sealing tire damage, inadvertent opening of the discharge valve, or opening of the discharge valve performed with unawareness, in this operating state can result in sealant emerging into the surroundings at high pressure.
Aside from the possible contamination of articles of clothing and the surroundings, irreparable damage to the compressor may also occur depending on the present structural arrangement of the discharge valve. Such incorrect operation by the user is not as unlikely as one might presume, because a typical average user tends to be unfamiliar with handling the air compressor to be used, and is additionally distracted by increased stress when performing sealing in the event of a tire-based breakdown.